While HPLC, GC, or the like has been known as a method for quantitatively analyzing a sample conventionally, NMR is also being used.
For a method for quantifying a compound containing an oxygen-17 nucleus, Japanese Patent Application Publication No. 2004-286712 (patent document 1) discloses a method for NMR-measuring a reference material and a sample similarly, using as a reference material a substance with a resonance frequency of oxygen-17 nucleus which is different from that of a sample. Furthermore, a method for conducting measurement using a coaxial double sample tube is disclosed in which a sample and a reference material are put into an inner tube and an outer tube, respectively.
However, there may be a problem that it is not possible to ensure a quantitative capability of NMR, unless a substance with a resonance frequency of oxygen-17 nucleus which is different from that of a sample is selected for a reference material for each sample.
Furthermore, there may be a problem that whenever samples are replaced, reference materials have to be replaced accordingly, and additionally, it is not possible to conduct quantification by using a volatile reference material.